If
a family tree were done all the way back to the beginning of life, the
generational connections of trillions upon trillions of living things across
all species of plants and animals would show, perched on top like a lonely and
forlorn Christmas-tree angel, the Mother of All Life: Luca. Luca is the acronym
for “Last Universal Common Ancestor.” According to scientists, Luca, a simple single
cell, first existed four billion years ago when Earth itself, at 560 million
years of age, surely was still teething.
Some
scientists believe that Luca emerged from deep-sea vents swirling with gases
and furnace temperatures caused by the volcanic magma erupting on the sea
floor. The dramatic interaction of those elements, together with both sea water
and critical metals found there, would have been enough to create the first life.
We’ll call this sine-qua-non Evolutionary
Vent, whenever and wherever it first happened, the Big E-Vent. Devotees of the Big
E-Vent, notably evolutionary biologist Dr. William Martin of Heinrich Heine
University in Germany, have isolated a mere 355 genes, out of the typical tens
of millions of genes in a living organism, that are common to living things and
therefore believed to have been the very genes of Luca. Because the functions
of those few genes are inadequate to sustain life, the Big E-Vent scientists
believe that Luca must have only been “half alive” or half of a living thing,
depending for its life on chemicals from its environment to sustain it.
If
true, Luca was the first chimera. Instead of something a like part human, part
monkey creature, proto-chimeric Luca, with each ocean wave must have lurched from
vent to vent, doomed to a semi-existence as half living bacterium-like cell,
half zombie-like amalgam of metals and chemicals.
Others
dispute the promoters of the Big E-Vent with all their plumes of gases, heavy
metals, and raucous volcanic noise. They say that life originated more casually
in warm shallow pools. Darwin himself believed this, believing that life
evolved from “warm little ponds.” The scientists who believe in the less
dramatic and laid-back pool theory we’ll call the Pool Parties. The Pool
Parties also point to the essential function of ultraviolet light, critical not
just for sunbathing or drying out after a swim but for its role as an energy source
capable of causing the chemical reaction that animated the first living cell
spawning all of life on Earth.
One
such patron among the Pool Parties, Dr. John Sutherland, a chemist at the
University of Cambridge, said that the chemistry does not support the Big
E-Vent theory, and he criticized the study for its lack of testing with chemical
simulations. Sutherland also had this to say about the proposition that Luca
could only have been half-alive, half chemical zombie: “It’s like saying I’m
half-alive because I depend on my local supermarket.”
In
conclusion, I will say that Dr. Sutherland sounds very reasonable, but I highly
doubt he’s ever wandered into a Safeway well after midnight and seen as I have
the creatures who are in there shopping at that hour.
